Northern Ireland’s once rich seas are in danger of turning into dead zones devoid of marine life.

One of the world’s leading maritime experts has said that the environmental devastation in our waters is already so severe that the abundance of fish that once lived in the Irish Sea has now been replaced by huge areas of sand and mud that are barren of life.

All this week, the Belfast Telegraph is running a special ‘Save Our Seas’ series, which will reveal the devastating pressures that are draining our seas and waterways of life.

Over the week we will uncover the shocking evidence of how our treasured marine and aquatic environments have been decimated by years of neglect and failure to curb over-exploitation, leaving Northern Ireland at risk of major EU fines on a number of fronts.

The series will raise disturbing issues about the priority given by Stormont to protecting our environment and ask whether an independent watchdog needs to be urgently created to protect our waterways. We have discovered a number of shocking findings:

Just three out of every 100 young salmon that leave their rivers to feed at sea are surviving to come back to spawn.

Less than a third of our rivers and lakes are in good condition — three years into a programme supposed to improve them.

An experimental cockle fishery in Belfast Lough closed following just two years of exploitation, after the Department of Agriculture permitted what was termed a ‘free for all’ by fishermen.

A whole arsenal of deadly environmental problems is building up beneath the surface of the water, according to Professor Callum Roberts, who has issued a stark wake-up call about the state of our oceans.

The future he forecasts in his book, Ocean of Life, is a terrifying one in which 40 or 50 years from now the oceans are riddled with dead zones and elsewhere the jellyfish is king.

Not only have we still not got to grips with the overfishing of our seas, but that conundrum is nothing compared to the onslaught from forces such as climate change, pollution spilling down from the land, the build-up of underwater noise and the ever-growing gyres of litter.

The acidification of the oceans has already killed off rich coral reefs across the globe, and plankton, which form the entire foundation of the marine food web, could be next in line.

“Two hundred years ago, the Irish Sea was described as an amazing cornucopia of life with abundant cod, halibut, skate and even angel sharks,” Prof Roberts told the Belfast Telegraph.

“Now it’s largely sand and mud over large areas of the Irish Sea.”

“We’re already seeing animals change their range as the seas warm. (For example) the mauve stinger jellyfish that killed all those salmon in north Antrim. Their natural range is down towards the Mediterranean and the Bay of Biscay but they have been moving north because of the warming seas.”

Meanwhile, nutrient-rich pollution pouring into our rivers, lakes and seas is starting to create ‘dead zones’ where all the oxygen is used up and nothing can survive.

“This is one of the reasons why we fear a future in which the jellyfish are the kings of the sea,” Prof Roberts said.

“They seem to thrive on the collection of the very changes we are producing in the sea — warm water, low oxygen, their skeleton is not affected by acidification and they like it when we are overfishing their competitors.”

Many of the fish we once lived on have plummeted to alarming levels, including cod, sole and whiting, but Prof Roberts says it’s no cause for celebration that our prawn fishery is doing so well.

“These are fisheries of last resort — they are all that is left when everything else is gone,” he said.

His comments are echoed by Richard Devlin of Northern Ireland Marine Task Force.

“Fifty years ago we were landing the top predators — cod, haddock, halibut. Now we are landing the scavengers as the fish stocks decline,” he said.

Throughout this week, the Belfast Telegraph will be scrutinising the health of Northern Ireland’s aquatic habitats.

Tomorrow we examine the threats bringing our seas to the limits of what they can withstand, and on Wednesday we investigate the coastal habitats caught between the pressures of land and sea. On Thursday we look at our rivers and lakes and on Friday we explore the often-dismissed upland bog habitats that could make all the difference to our ability to cut our carbon footprint.

An ocean of problems... the crucial issues facing our endangered seas and rivers

A global warming hotspot

The Irish Sea is at the centre of a global warming hotspot where the sea is warming faster than elsewhere. A study by the University of Bristol on the seas round the British Isles, the Bay of Biscay and the North Sea, found the most intensive warming trends in the southern and eastern North Sea and the Irish Sea. It is in those hotspots that some of the most marked changes in composition of fish species groups have taken place.

Spawning salmon at lowest level

Last year the number of salmon returning to our rivers fell to lowest levels ever — 3%. For every 100 young salmon that left the rivers where they hatched and headed out to sea to feed, just three survived to return to spawn. In 1976 the Fisheries Conservancy Board predicted commercial netting would cause problems. By 1994 up to 89% of River Bush salmon returning to the Irish coast were taken by commercial nets.

Cockle beds nearly wiped out

IN just two years, a now closed experimental fishery set up in Belfast Lough to exploit its cockle beds has all but destroyed the resource, according to one fisherman. He says just two boats used suction dredging in the first years, using techniques suggested by scientists, yet in 2009 the Department of Agriculture allowed 14 boats to fish, using methods counter to advice given. “They’ve wiped out the cockle beds,” he said.

Little progress to improve rivers

Three years ago, just 28% of Northern Ireland’s rivers and lakes were found to be in good condition and the DoE made a commitment to get that figure up to 59% by 2016. But the latest figures reveal that despite promising trends with nutrient levels, the figure is still around the 28-29% mark. DoE officials admit that without investment, it will be a “challenge” to reach that 59% target, and we could face EU fines.

Pollution leading to fish kills

TWO of our best known rivers have been affected by pollution leading to oxygen depletion. There are sensitive areas near the mouths of the Lagan and the Quoile where high nutrient levels have combined with the artificial impounding of the rivers to cause oxygen levels to plummet under certain conditions. While measures have been put in place to combat this, the phenomenon has led to fish kills in the Quoile.

Dredging destroying ecosystem

Forty years ago, up to 400 anglers at a time would enter the big competitions up at Benone, according to the Northern Ireland Federation of Sea Anglers. Now that is down to 30 and the competition organisers are contemplating dropping the minimum-size requirement as the fish caught are much smaller than they used to be. They say dredging is destroying the undersea ecosystem and not giving it a chance to recover.

Irish Sea sole stocks depleted

Scientists advise that sole should no longer be caught in the Irish Sea to allow it time to recover following years of decline. The Irish Sea sole stock is classified as having reduced reproductive capacity — in other words it is depleted. Spawning stock biomass has continuously declined since 2001 and reached its lowest level in 2009. Fishing mortality has dropped since but scientists are recommending zero catch in 2012.

Litter on beaches rises by 340%

The highest density of litter on UK beaches is in Northern Ireland where volunteers taking part in the most recent Marine Conservation Society Beachwatch clean-up gathered a staggering 4,948.5 items/km. That was a 340% increase on the previous year, although the number of beaches cleaned had risen. The most common items were plastic fragments, plastic lids, polystyrene, sweet wrappers and cord.

Only one surviving eel fishery

Eel populations have plummeted across Europe and all fisheries here have been closed except one in Lough Neagh, supplemented by elvers from elsewhere. Before 1983, Lough Neagh had, on average, 12m elvers arriving from the sea but by 2011 this had plunged to 12,000. Government scientists are working with the Lough Neagh Fishermen's Cooperative to produce one of the most detailed scientific surveys of eel in Europe.

EU may fine us over infractions

Northern Ireland faces an £8m fine from Europe for its failure to protect scarce wildlife in Strangford Lough. The EU has embarked on infraction proceedings, which could culminate in fines because of Stormont’s failure to protect the lough’s unique mussel beds from destruction. Strangford Lough is the only place in the world where these modiolus bivalves form living reefs, which support up to 100 other marine species.